A 19-year-old female underwent repair of complex congenital heart disease (atrial and ventricular septal defect with a criss-cross atrioventricular relationship) in infancy. Because or recurrent palpitations she underwent an electrophysiology study. Atypical atrioventricular nodal reentrant tachycardia was diagnosed. Catheter ablation was performed successfully using cryothermal energy. The diagnostic and therapeutic approach is discussed
